The telecommunication networks provide a growing number of packet-based services, such as Voice over IP (VoIP), gaming, video conferencing, IP Radio (RoIP), IP Television (IPTV), including Broadcast TV (BTV), pay per view (PPV), video-on-demand (VOD), and interactive TV. These services all share parts of the same distribution network, and in the access portion of the network touching the residence, typically share that same last mile network. In this shared environment, they may interact with each other in a negative manner. Each service has unique quality-of-service (QoS) needs. Various class-of-service (CoS) mechanisms are implemented in the networks to manage these needs. Available assessment tools typically monitor and analyze network-level service performance in terms of Quality of Service (QoS) or compliance such as with service level agreements (SLAs), using packet-based measurements such as jitter, loss, and delay for a single service.
Triple Play services deployed by service providers include services of three different service types: voice, video, and data, wherein the voice service is usually a VoIP service, the data services include email, internet browsing, FTP, etc., and the video services, also called IP Video or IPTV, include BTV, VOD, PPV. Services of the different types are typically provided to a subscriber simultaneously over various distribution networks. In those deployments where the technology used in the “last mile” of the access link has limited band width, for example ADSL or VDSL copper based access links, the demand for band width by the individual services could impact another service or can exceed the available band width. As an example, a subscriber is using a PC to access the public internet with the Data service, one or more VoIP calls are present, and a TV is turned on to access the IP Video service.
As the three different services travel across the distribution networks and, in particular, the access portion to the subscriber's premise and end point equipment, it is critical that the voice and video services meet the QoS parameters specific to each service in order to deliver the proper Quality-of-Experience (QoE) to the subscriber.
In today's telco test environment, the three components of the triple play services are tested individually. Known in the art are devices and methods for measuring QoS parameters for a single service, such as U.S. Pat. No. 6,888,801 issued May 3, 2005 to Hock and U.S. Pat. No. 6,985,945 issued Jan. 10, 2006 to Farhat et al. for voice, and U.S. Pat. No. 6,880,115 issued Apr. 12, 2005 to Abraham et al. and U.S. Pat. No. 7,010,598 issued Mar. 7, 2006 to. Sitaraman et al. for video. However, the interaction between services is not tested and validation of the Class-of-Service (CoS) mechanisms is not accomplished, therefore new service installations and troubleshooting procedures may miss important interactions effecting the QoE.
Passive monitoring of more than one service received together is disclosed in U.S. Patent Applications Nos. 20060198634 published Sep. 7, 2006 in the name of Ofalt et al. and 20060062216 published Mar. 23, 2006 in the name of Li et al.
The Ofalt reference teaches a multi-frequency tap apparatus for testing passive optical networks, which taps off a small amount of power without interrupting transmission to measure loss of optical power on the physical layer. In one embodiment the apparatus is a Triple Play Power Meter (TPPM), testing only power levels for the optical frequencies associated with components of the triple play service.
The Li reference discloses an apparatus consisting of a splitter and a switching fabric between an ingress and egress, so that at least some packets are copied to a QoS measuring block. The ingress receives packets of different types and QoS parameters are measured among one or more groups of packets.
The apparatuses disclosed in the aforementioned two applications provide passive monitoring only, since they measure through traffic destined to a user; however, they are not designed to perform active testing, wherein QoS parameters are evaluated for any predetermined configuration of services, therefore, there is the need to perform active testing of multiple services. Additionally, the presence of a receiving client rendering the service may affect the measurements, for example: in case of the receiver malfunctioning when multiple packets are lost at the receiver and requested to be retransmitted, i.e. the service performance is measured as affected by the client equipment.
When video flows are mixed with data and voice flows, network planning and engineering become even more challenging in terms of meeting the demands for the increase in bandwidth required to transport triple-play services. Complexity increases as new signaling protocols, such as Internet group management protocol (IGMP) for broadcast video and real-time streaming protocol (RTSP) for video on demand (VOD) services, are introduced. The dynamic nature of video flows is affected by viewing habits, channel changing loads, and dynamic VOD media requests. All of these factors add to the demands and complexity of delivering the required CoS.
U.S. Patent Applications 20030223376 published Dec. 4, 2003 in the name of Elliott et al. and 20040208129 published Oct. 21, 2004 in the name of Old et al. represent conventional systems for active testing of a network. In such systems, a test data generator generates traffic containing multiple streams associated with different services. Transmitted over the network, the traffic is then received by another apparatus and the quality of transmission is evaluated based on knowledge of the generated traffic. A variant of such systems is a single device, acting as the traffic generator and the receiver, accompanied by a loop cable within the network for reversing the traffic disclosed in.
While useful for pre-production testing, such systems would disrupt functionality of a network in production with their bulk traffic. Also, such systems do not perform testing of real life services provided by servers on the network, since there is a difference between testing a network capacity and a service. Of course, service performance depends on network capacity and is negatively affected by network bottlenecks. However, the service performance additionally depends on a service provider, its work load and configuration, and on the actual routes the flows take when the real service is tested. A traffic generator can not emulate the real service and actual routes taken by the real service flows.
It is known in the art of telecommunication to use apparatus that simulate client premises equipment. For example, U.S. Patent Application 20060067237 published Mar. 30, 2006 in the name of Burns et al. teaches a test apparatus that mimics a customer device and tests network connections between the service provider and the device.
U.S. Pat. No. 7,111,204 issued Sep. 19, 2006 in the name of Couturier et al. teaches a system for creating a plurality of ‘synthetic users’, each ‘synthetic user’ implementing a plurality of ‘synthetic transactions’ for cost and resource-effective load testing of a network server and the associated application services provided thereby and generate statistically-sufficient data. The system disclosed in the Couturier reference provides service testing, i.e. testing a capacity of the service provider; however, the Couturier system disrupts network traffic and does not test a service received by one particular user in real-life conditions of a deployed server in a production network.
It is an object of the present invention to overcome the shortcomings of the prior art and provide a device and a method for simultaneous testing multiple services received via a shared network access link.